Reseting the root password in Linux?

Holding escape, nor any of the f keys or anything apparently does not get me the grub boot prompt. I need to send a file over the parallel port using the cat command.

I need to send a file over the parallel port using the cat command.

If you can do it as root, you can do it as sudo
Run man sudo in a terminal or google it.

Holding escape, nor any of the f keys or anything apparently does not get me the grub boot prompt

Depends entirely upon what version of GRUB, what BIOS version etc.
We have no way of guessing what you installed and onto what.

If you have a USB keyboard, on older machines you cannot do anything with it until the USB drivers are loaded, not even select a boot option in GRUB

regards

Apparently there is some kind of rare exception for printing system, you need to actually give the root password. I tried sudo, and it asks me for the root password.

I was never able to find out the default root pw for emc2, I googled a lot. It used to not be set by default or something?

It is ubuntu version 10.04 lts. I really need to fix this, can anyone help?

I tried sudo, and it asks me for the root password.

Have you tried just putting in your own password?

The whole point of sudo is that it prevents lots of different people knowing the root password, so it is not going to ask you for it, you should not know it.

I need to send a file over the parallel port using the cat command.

If you tell us exactly what commands you are using etc. may be able to assist more.

In addition to the issues in this link
ubuntuforums.org/showthread.php?t=2060188

there is the little matter of parport driver blacklisting ( or redirecting to null ) in distros, to prevent parport_pc etc grabbing it before linuxcnc
and preventing linuxcnc from working.

Heya? Otherwise I need to get a cd image written and re-install everything, I guess.